1. Technical Field
The present invention relates to a horizontal articulated robot equipped with an angular velocity sensor.
2. Related Art
In the past, there has been known a horizontal articulated robot which suppresses vibration caused in the arm using an angular velocity sensor for detecting the angular velocity of the arm as described in JP-A-2005-242794 (Document 1). In the horizontal articulated robot described in Document 1, a first arm rotatable with respect to the base rotates due to the drive force of a first drive source, and at the same time, the rotational angle of the first drive source is detected by the first angle sensor. Further, the angular velocity of the first arm with respect to the base is detected by an angular velocity sensor mounted on the first arm. Further, the drive amount of the first drive source is controlled based on the angular velocity detected by the angular velocity sensor so that the vibration caused in the first arm can be suppressed.
Incidentally, the vibration caused in the first arm is generally amplified by another arm coupled to the first arm, and then reaches an end effector of the horizontal articulated robot. Therefore, in order to suppress such a vibration of the end effector, it is effective to perform such damping control as described above on the first drive source.
On the other hand, in order to drive the angular velocity sensor described above, it becomes necessary to connect a variety of electric wires such as a wire for supplying the angular velocity sensor with electricity or a wire for transmitting the detection signal of the angular velocity sensor between the angular velocity sensor and the controller. Further, such electric wires are also required for the drive sources besides the angular velocity sensor, and are generally connected to an external controller through a hollow base. Further, if the configuration in which the angular velocity sensor described above is mounted on the first arm is adopted, it results that such an electric wire required to such an angular velocity sensor is also connected between the first arm and the controller through the base.
In this occasion, the track drawn by the first arm with respect to the base generally includes a larger number of tracks with small curvature compared to the tracks drawn by other arms with respect to the base. Therefore, the chances of folding the electric wires drawn from the first arm increase, and further, the curvature in the folded portions also becomes smaller compared to the electric wires drawn from other arms. Therefore, it is required for the horizontal articulated robot performing damping control using the angular velocity sensor to enhance the durability of such an electric wire connected to the angular velocity sensor.